American vehicles were 9 years old on average in 2013, which is 2 years older than the mean age for cars before the recession, according to a new study using data from more than 68,000 vehicles in Los Angeles, Denver and Tulsa.
Collecting real-time data since 1995, researchers have found that as people bought fewer new vehicles due to the economic slump, the average age of the U.S. fleet increased and may have resulted in more emissions and dirtier air.
"This paper shows that a small change in consumer behavior can have an unexpectedly large impact on average fleet age," said Russell R. Dickerson, an atmospheric chemist at the University of Maryland, College Park.
Lead researcher Gary A. Bishop, an atmospheric scientist from the University of Denver, did offer the caveat that because people were driving less during the recession, older vehicles may not necessarily have contributed to poorer air quality.
But it's important to note that an average age of 9 years puts the U.S. fleet at a disadvantage since many engine technological advancements have arrived in the interim.
Gasoline direct-injection engines first came to the U.S. market when the redesigned Audi A6 launched in 2004. The technology, which was previously only available on diesel engines, lets fuel go straight to the combustion chamber, resulting in gas that burns more evenly and in improved mileage for the car.
Chrysler is one automaker that will soon be adding such engine improvements, putting direct injection and other new technology in its Pentastar V-6 lineup. The refreshed Jeep Grand Cherokee due in late 2015 will reportedly feature the first updated 3.6-liter V-6, according to Automotive News.
The implementation of direct-injection powertrains has boosted recent models when it comes to efficiency and mileage; stop-start technology and all-electric vehicles have also advanced the auto industry's efforts to reduce emissions.
The average 9-year-old car definitely won't have stop-start technology, a newer gas-saving system featured on just 500,000 or so new cars sold in the U.S. in 2013.
Shown in AAA research to save drivers 5 to 7 percent on gas costs each year, stop-start technology automatically switches off a vehicle's engine while it's idle, such as when a driver stops at a red light. While it's frequently seen on hybrid models, the technology is slowly making its way into traditional engines, according to TIME.
The rising popularity of the plug-in vehicle is another recent innovation for the auto industry, with all-electric car sales rising 50 percent this year compared with 2013. While Tesla's famous $70,000 Model S may make headlines more often, more affordable green rides that have been popular include the Honda Accord Hybrid, which starts at around $29,000; the Nissan Leaf, an all-electric model that starts at about $29,000; and the Ford Fusion Hybrid, starting at $26,270.